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Redos
A regular expression denial of service (ReDoS) is an algorithmic complexity attack that produces a denial-of-service by providing a regular expression and/or an input that takes a long time to evaluate. The attack exploits the fact that many regular expression implementations have super-linear worst-case complexity; on certain regex-input pairs, the time taken can grow polynomially or exponentially in relation to the input size. An attacker can thus cause a program to spend substantial time by providing a specially crafted regular expression and/or input. The program will then slow down or become unresponsive. Description Regular expression ("regex") matching can be done by building a finite-state automaton. Regex can be easily converted to nondeterministic automata (NFAs), in which for each state and input symbol, there may be several possible next states. After building the automaton, several possibilities exist: * the engine may convert it to a deterministic finite-state ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Algorithmic Complexity Attack
An Algorithmic complexity Attack (ACA) is a form of attack in which the system is attacked by an exhaustion resource to take advantage of Best, worst and average case, worst-case performance. Worst-case performance through a back-end algorithm results in the exhaustion of the server, this creates algorithmic complexity vulnerabilities. According to Adam Jacobson and Dr. David Renardy, research scientists froTwo Six Labs "An AC Time vulnerability causes denial of service by exhausting CPU while AC Space vulnerabilities exhaust RAM or disk space." Examples of ACA attacks are zip-bombs, billion laughs, and ReDoS which are Malicious files aimed to render a program useless. Additionally, as stated by the Cybersecurity and Infrastructure Security Agency, a department within the United States Department of Homeland Security, Department of Homeland Security, “A denial-of-service (DoS) attack occurs when legitimate users are unable to access information systems, devices, or other network ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Regular Expression
A regular expression (shortened as regex or regexp; sometimes referred to as rational expression) is a sequence of characters that specifies a search pattern in text. Usually such patterns are used by string-searching algorithms for "find" or "find and replace" operations on strings, or for input validation. Regular expression techniques are developed in theoretical computer science and formal language theory. The concept of regular expressions began in the 1950s, when the American mathematician Stephen Cole Kleene formalized the concept of a regular language. They came into common use with Unix text-processing utilities. Different syntaxes for writing regular expressions have existed since the 1980s, one being the POSIX standard and another, widely used, being the Perl syntax. Regular expressions are used in search engines, in search and replace dialogs of word processors and text editors, in text processing utilities such as sed and AWK, and in lexical analysis. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Regular Expression
A regular expression (shortened as regex or regexp; sometimes referred to as rational expression) is a sequence of characters that specifies a search pattern in text. Usually such patterns are used by string-searching algorithms for "find" or "find and replace" operations on strings, or for input validation. Regular expression techniques are developed in theoretical computer science and formal language theory. The concept of regular expressions began in the 1950s, when the American mathematician Stephen Cole Kleene formalized the concept of a regular language. They came into common use with Unix text-processing utilities. Different syntaxes for writing regular expressions have existed since the 1980s, one being the POSIX standard and another, widely used, being the Perl syntax. Regular expressions are used in search engines, in search and replace dialogs of word processors and text editors, in text processing utilities such as sed and AWK, and in lexical analysis. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Denial-of-service Attacks
In computing, a denial-of-service attack (DoS attack) is a cyber-attack in which the perpetrator seeks to make a machine or network resource unavailable to its intended users by temporarily or indefinitely disrupting services of a host connected to a network. Denial of service is typically accomplished by flooding the targeted machine or resource with superfluous requests in an attempt to overload systems and prevent some or all legitimate requests from being fulfilled. In a distributed denial-of-service attack (DDoS attack), the incoming traffic flooding the victim originates from many different sources. More sophisticated strategies are required to mitigate this type of attack, as simply attempting to block a single source is insufficient because there are multiple sources. A DoS or DDoS attack is analogous to a group of people crowding the entry door of a shop, making it hard for legitimate customers to enter, thus disrupting trade. Criminal perpetrators of DoS attacks of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
High Orbit Ion Cannon
High Orbit Ion Cannon (HOIC) is an open-source network stress testing and denial-of-service attack application designed to attack as many as 256 URLs at the same time. It was designed to replace the Low Orbit Ion Cannon which was developed by Praetox Technologies and later released into the public domain. The security advisory for HOIC was released by Prolexic Technologies in February 2012. Development HOIC was developed during the conclusion of Operation Payback by the hacktivist collective Anonymous. As Operation Payback concluded there was massive pressure on the group from law enforcement agencies, which captured and prosecuted more than 13 individuals connected with the group. This forced many members of the group to rethink their strategies and subsequently this part of the group launched Operation Leakspin. However a large part of Anonymous remained focused on launching opt-in DDoS attacks. However the Low Orbit Ion Cannon was not powerful enough to launch attack ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Low Orbit Ion Cannon
Low Orbit Ion Cannon (LOIC) is an open-source network stress testing and denial-of-service attack application written in C#. LOIC was initially developed by Praetox Technologies, however it was later released into the public domain and is currently available on several open-source platforms. Use LOIC performs a DoS attack (or, when used by multiple individuals, a DDoS attack) on a target site by flooding the server with TCP, UDP, or HTTP packets with the intention of disrupting the service of a particular host. People have used LOIC to join voluntary botnets. The software inspired the creation of an independent JavaScript version called ''JS LOIC'', as well as LOIC-derived web version called ''Low Orbit Web Cannon''. These enable a DoS from a web browser. Countermeasures Security experts quoted by the BBC indicated that well-written firewall rules can filter out most traffic from DDoS attacks by LOIC, thus preventing the attacks from being fully effective. In at leas ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Denial-of-service Attack
In computing, a denial-of-service attack (DoS attack) is a cyber-attack in which the perpetrator seeks to make a machine or network resource unavailable to its intended users by temporarily or indefinitely disrupting services of a host connected to a network. Denial of service is typically accomplished by flooding the targeted machine or resource with superfluous requests in an attempt to overload systems and prevent some or all legitimate requests from being fulfilled. In a distributed denial-of-service attack (DDoS attack), the incoming traffic flooding the victim originates from many different sources. More sophisticated strategies are required to mitigate this type of attack, as simply attempting to block a single source is insufficient because there are multiple sources. A DoS or DDoS attack is analogous to a group of people crowding the entry door of a shop, making it hard for legitimate customers to enter, thus disrupting trade. Criminal perpetrators of DoS attacks ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Denial-of-service
In computing, a denial-of-service attack (DoS attack) is a cyber-attack in which the perpetrator seeks to make a machine or network resource unavailable to its intended users by temporarily or indefinitely disrupting services of a host connected to a network. Denial of service is typically accomplished by flooding the targeted machine or resource with superfluous requests in an attempt to overload systems and prevent some or all legitimate requests from being fulfilled. In a distributed denial-of-service attack (DDoS attack), the incoming traffic flooding the victim originates from many different sources. More sophisticated strategies are required to mitigate this type of attack, as simply attempting to block a single source is insufficient because there are multiple sources. A DoS or DDoS attack is analogous to a group of people crowding the entry door of a shop, making it hard for legitimate customers to enter, thus disrupting trade. Criminal perpetrators of DoS attacks o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
E-mail Scanner
Electronic mail (email or e-mail) is a method of exchanging messages ("mail") between people using electronic devices. Email was thus conceived as the electronic ( digital) version of, or counterpart to, mail, at a time when "mail" meant only physical mail (hence '' e- + mail''). Email later became a ubiquitous (very widely used) communication medium, to the point that in current use, an email address is often treated as a basic and necessary part of many processes in business, commerce, government, education, entertainment, and other spheres of daily life in most countries. ''Email'' is the medium, and each message sent therewith is also called an ''email.'' The term is a mass noun. Email operates across computer networks, primarily the Internet, and also local area networks. Today's email systems are based on a store-and-forward model. Email servers accept, forward, deliver, and store messages. Neither the users nor their computers are required to be online simult ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Algorithmic Complexity Attacks
Algorithmic may refer to: *Algorithm, step-by-step instructions for a calculation **Algorithmic art, art made by an algorithm **Algorithmic composition, music made by an algorithm ** Algorithmic trading, trading decisions made by an algorithm ** Algorithmic patent, an intellectual property right in an algorithm *Algorithmics, the science of algorithms **''Algorithmica'', an academic journal for algorithm research **Algorithmic efficiency, the computational resources used by an algorithm **Algorithmic information theory, study of relationships between computation and information **Algorithmic mechanism design, the design of economic systems from an algorithmic point of view **Algorithmic number theory, algorithms for number-theoretic computation ** Algorithmic game theory, game-theoretic techniques for algorithm design and analysis * Algorithmic cooling, a phenomenon in quantum computation *Algorithmic probability In algorithmic information theory, algorithmic probability, also known ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cyberwarfare
Cyberwarfare is the use of cyber attacks against an enemy state, causing comparable harm to actual warfare and/or disrupting vital computer systems. Some intended outcomes could be espionage, sabotage, propaganda, manipulation or economic warfare. There is significant debate among experts regarding the definition of cyberwarfare, and even if such a thing exists. One view is that the term is a misnomer, since no cyber attacks to date could be described as war. An alternative view is that it is a suitable label for cyber attacks which cause physical damage to people and objects in the real world. Many countries including the United States, United Kingdom, Russia, China, Israel, Iran, and North Korea have active cyber capabilities for offensive and defensive operations. As states explore the use of cyber operations and combine capabilities, the likelihood of physical confrontation and violence playing out as a result of, or part of, a cyber operation is increased. However, me ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Intrusion Detection System
An intrusion detection system (IDS; also intrusion prevention system or IPS) is a device or software application that monitors a network or systems for malicious activity or policy violations. Any intrusion activity or violation is typically reported either to an administrator or collected centrally using a security information and event management (SIEM) system. A SIEM system combines outputs from multiple sources and uses alarm filtering techniques to distinguish malicious activity from false alarms. IDS types range in scope from single computers to large networks. The most common classifications are network intrusion detection systems (NIDS) and host-based intrusion detection systems (HIDS). A system that monitors important operating system files is an example of an HIDS, while a system that analyzes incoming network traffic is an example of an NIDS. It is also possible to classify IDS by detection approach. The most well-known variants are signature-based detection (recogni ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
